The invention relates to a coupling whose switching is dependent on the rotational speed, one coupling half thereof being held in fixed connection with the other coupling, half up to the switching speed, by being supported on several switching elements which are centrifugally controlled and spring loaded.
In a known coupling of this type the switching elements are distributed around the coupling axis and shiftably positioned on radially arranged bolts against the force of a spring which is associated with each individual switching element. The separation of the fixed connection of both coupling halves is only achieved when all switching elements have moved radially outwards as a result of the centrifugal force acting on them. As the moving of each individual switching elements is independent, of the others, the danger of the radial movement of the switching elements not being achieved simultaneously exists because of different adjustment to springs and different load of the switching elements supporting one coupling half. An exact adjustment to the switching speed is therefore difficult. The unguaranteed synchronous radial movement of the switching elements presents the further disadvantage that one coupling half can be swung, after removing the support on one part of the one coupling half, with the effect that jamming occurs. This also renders the adjustment of an exact switching speed difficult.
The direct support of the switching elements on the one coupling half presents the disadvantage that the pressure between the switching elements and the one coupling half, and with that the resistance of the switching elements against being moved by centrifugal force, is influenced by the axial component of the circumferential force of the torque. This coupling is therefore not independent of the torque (German Auslegeschrift 2 300 216).
The object of the invention consists in making a coupling whose switching is dependent on the rotational speed of the above named type in which the switching speed can be easily adjusted.